Iyassou Author

Level 1

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GPT help

https://discussions.apple.com/thread/4144252?answerId=26125763022#26125763022

Output of sudo fdisk /dev/rdisk0 :

Disk: /dev/rdisk0

geometry: 60801/255/63 [976773168 sectors]

Signature: 0xAA55

Starting Ending

#: id cyl hd sec - cyl hd sec [ start - size]

------------------------------------------------------------------------

1: EE 1023 254 63 - 1023 254 63 [ 1 - 409639] <Unknown ID>

2: 07 1023 254 63 - 1023 254 63 [ 409640 - 469338128] HPFS/QNX/AUX

3: AB 1023 254 63 - 1023 254 63 [ 469747768 - 1269536] Darwin Boot

4: 07 1023 254 63 - 1023 254 63 [ 471017472 - 76855296] HPFS/QNX/AUX

I am using GPT fdisk (or gdisk).

I don't remember all that I've tried to do, but the changes that I had made were: changing the 4th partition's id to 07 (then because of a confusion, the 2nd partition's id to 07). That's it.

MacBook Pro, Mac OS X (10.7)

Posted on Jun 15, 2014 10:24 AM

37 replies

Loner T

Level 9

59,606 points

Jul 4, 2014 1:50 PM in response to Iyassou

The answer here should be yes. This can be changed since you have the ability to access the disk in target disk mode. There is also a backup of the GPT that can be reloaded, if necessary. I assume you have the backup file on the working MAC and not on the original non-working MAC. If not, I would copy it after you do a write.

Please try booting to MAC OS X on the "broken" MAC after you write and power cycle it. Using the ALT key should tell you quickly if the changes are sufficient or not. Running an additional bless may not be required.

Iyassou Author

Level 1

0 points

Jul 4, 2014 1:56 PM in response to Loner T

THANK YOU!! I CAN NOW BOOT INTO MAC!! Although, I have to ask, is there any way to save my BOOTCAMP partition?

Loner T

Level 9

59,606 points

Jul 4, 2014 2:01 PM in response to Iyassou

Yes, we need to address the Bootcamp part now. If you used the ALT key, did a bootable Windows also show up? Do you see Bootcamp in Finder and a Bootcamp volume?

Iyassou Author

Level 1

0 points

Jul 5, 2014 11:14 AM in response to Loner T

When I startup my mac pressing ALT I can see a "Windows" volume, but when I boot into it, I get the error message "Missing Operating System".

In Finder, there is no BootCamp volume.

ALTHOUGH, in Disk Utility I can see my BootCamp volume under the name "disk0s4" . It's about 180GB, which was the same space I allocated to my BootCamp partition; so yeah, my BootCamp partition is there, but I can't access it.

Loner T

Level 9

59,606 points

Jul 5, 2014 11:33 AM in response to Iyassou

If you have the Windows Installation media, you can do startup repair as noted here...

http://windows.microsoft.com/en-us/windows7/products/features/startup-repair

Depending on how badly the Windows side is corrupted, you may be able to re-install, without losing your data. I assume you have Windows 7. Windows XP has a recovery console as well.

Iyassou Author

Level 1

0 points

Jul 6, 2014 1:02 AM in response to Loner T

The start-up repair did not work 😟 . But I have a question, the format of my Windows partition is now FAT (MS-DOS), its original format was NTFS. Could this be the problem preventing it from not booting?

Loner T

Level 9

59,606 points

Jul 6, 2014 5:36 AM in response to Iyassou

It is one likely problem. Disk Utility manipulations of Bootcamp partitions are fraught with issues. It will not boot if it is FAT. You can use testdisk (http://www.cgsecurity.org/wiki/TestDisk) to verify if this is the correct partition or not.

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